Annular bearing compartment

Abstract

The present invention relates to a bearing compartment for a turbomachine such as a gas turbine engine. The compartment includes a bearing compartment, to which is attached, on its front and rear sides, covers that allow for the passage of air through the compartment as well as past the compartment. In particular, the compartment includes a plurality of axially extending and circumferentially spaced apart sealed air cavities surrounding an oil cavity in the compartment; the bearing which supports a shaft extending through the engine is supported by the bearing. The compartment also includes a plurality of axially extending and circumferentially buffer air cavities surrounding the sealed air cavities, thereby providing additional insulate protection to the oil cavity.

We claim: 
     
       1. An annular bearing compartment for a turbomachine that includes a shaft extending axially through the machine, wherein said bearing compartment supports the shaft and is comprised of: an annular bearing assembly coaxial with the shaft, wherein said bearing assembly is comprised of an inner bearing race rotationally fixed to the shaft, an outer bearing race spaced radially outwardly of said inner bearing race, and a plurality of circumferentially spaced apart roller bearings between said inner and outer bearing races;   an annular bearing housing surrounding said bearing assembly, wherein said bearing housing includes an annular oil cavity, and said bearing assembly is constructed and arranged such that the roller bearings are located within the oil cavity;   a first wall spaced from and in sealing relation to said bearing housing, wherein said wall and housing cooperate to define a first annular air cavity that surrounds said oil cavity;   a second wall spaced from and in sealing relation to said first wall, wherein said first and second walls cooperate to define a second annular air cavity that surrounds the first air cavity.   
     
     
       2. An annular bearing compartment for a turbomachine that includes a shaft extending axially through the machine, wherein said bearing compartment supports the shaft and is comprised of: an annular bearing assembly coaxial with the shaft, wherein said bearing assembly is comprised of an inner bearing race rotationally fixed to the shaft, an outer bearing race spaced radially outwardly of said inner bearing race, and a plurality of circumferentially spaced apart roller bearings between said inner and outer bearing races;   an annular bearing housing surrounding said bearing assembly, wherein said bearing housing is comprised of axially facing front and rear walls that cooperate to define an annular oil cavity, and said bearing assembly is constructed and arranged such that the roller bearings are located within the oil cavity;   a front cover fixed to the front wall of said bearing housing and a rear cover fixed to the rear wall of said bearing housing, wherein each of said covers is comprised of spaced apart inner and outer walls; wherein the inner wall of said front cover is spaced from and in sealing contact with the front wall of the housing and define a front sealed air cavity adjacent to the oil cavity; and wherein the inner wall of said rear cover is spaced from and in sealing contact with the rear wall of the housing and define a rear sealed air cavity adjacent to the oil cavity;   and wherein the inner and outer walls of the front cover define a front buffer air cavity adjacent to the from sealed air cavity; and the inner and outer walls of the rear cover define a rear buffer air cavity adjacent to the rear sealed air cavity.   
     
     
       3. The bearing compartment of claim 2, wherein said front and rear sealed air cavities are in fluid communication with each other by means of axially extending channels, such channels extending from the front cover to the rear cover, wherein said channels and cover walls cooperate to define an annular, axially extending sealed air cavity adjacent to the oil cavity; and wherein said buffer air cavities are in fluid communication with each other by means of axially extending buffer air channels, said buffer air channels extending from the front cover to the rear cover, wherein said buffer air channels and cover walls cooperate to define an annular, axially extending buffer air cavity adjacent to the sealed air cavity. 
     
     
       4. The bearing compartment of claim 2, wherein said axially extending channels that provide fluid communication between said front and rear sealed air cavities are comprised of a plurality of front and rear sealed air cavities that are elliptically shaped and circumferentially spaced apart in said housing. 
     
     
       5. The bearing compartment of claim 2, wherein said axially extending channels that provide fluid communication between said front and rear buffer air channels are comprised of a plurality of front and rear sealed air cavities are elliptically shaped and are circumferentially spaced apart in said housing. 
     
     
       6. The bearing compartment of claim 2, wherein said axially extending channels that provide fluid communication between said front and rear sealed air cavities are comprised of a plurality of front and rear sealed air cavities that are elliptically shaped and circumferentially spaced apart in said housing, and wherein said axially extending channels that provide fluid communication between said front and rear buffer air channels are comprised of a plurality of front and rear buffer air cavities that are elliptically shaped and circumferentially spaced apart in said housing. 
     
     
       7. The bearing compartment of claim 6, wherein said sealed air cavity channels are radially inward of said buffer air cavity channels. 
     
     
       8. The bearing compartment of claim 2, wherein said front and rear covers each include a plurality of channels therein, and said bearing housing includes a plurality of channels therein, wherein the channels in said covers and housing cooperate to define a plurality of conduits that allow gases to flow through past the bearing compartment. 
     
     
       9. An annular bearing compartment for a turbomachine that includes a shaft extending axially through the machine, wherein said bearing compartment supports the shaft and is comprised of: an annular bearing assembly coaxial with the shaft, wherein said bearing assembly is comprised of an inner bearing race rotationally fixed to the shaft, an outer bearing race spaced radially outwardly of said inner bearing race, and a plurality of circumferentially spaced apart roller bearings between said inner and outer bearing races;   an annular bearing housing surrounding said bearing assembly, wherein said bearing housing is comprised of axially facing front and rear walls that cooperate to define an annular oil cavity, and said bearing assembly is constructed and arranged such that the roller bearings are located within the oil cavity;   a front cover fixed to the front wall of said bearing housing and a rear cover fixed to the rear wall of said bearing housing, wherein each of said covers is comprised of spaced apart inner and outer walls; wherein the inner wall of said front cover is spaced from and in sealing contact with the front wall of the housing and define a front sealed air cavity adjacent to the oil cavity; and wherein the inner wall of said rear cover is spaced from and in sealing contact with the rear wall of the housing and define a rear sealed air cavity adjacent to the oil cavity; and wherein said front and rear sealed air cavities are in fluid communication with each other by means of circumferentially spaced apart elliptical channels extending axially from the front cover to the rear cover to define an annular, axially extending sealed air cavity adjacent to the oil cavity;   and wherein the inner and outer walls of the front cover define a front buffer air cavity adjacent to the front sealed air cavity; and the inner and outer walls of the rear cover define a rear buffer air cavity adjacent to the rear sealed air cavity; and wherein said buffer air cavities are in fluid communication with each other by means of circumferentially spaced apart elliptical channels extending axially from the front cover to the rear cover to define an annular, axially extending buffer air cavity adjacent to the sealed air cavity.